392 THE CANADIAN NATURALIST. [Yol. VU. 



metallic lines are fine and nujnerous. The coloured stars are not 

 so hot, and are older. In consequence of their age they emit less 

 Yivid light. In them there is little or no hydrogen. Metallic 

 lines abound, but one also finds channelled spaces like the lines 

 of compounds, The temperature being lower, these latter can 

 exist whether they consist of atoms joined to others of the same 

 kind, or whether they contain groups of heterogeneous atoms- 

 In referring recently to this classification of Father Secchi and 

 the distribution of simple bodies in distant stars, Lockyer has 

 observed that the elements the atoms of which are lightest, are to 

 be found in the hottest stars, and that the metals with high 

 atomic weights are, on the contrary, met with in the colder stars ; 

 and he adds this— Are not the first elements the result of a de- 

 composition brought about by the extreme temperatures to which 

 the latter are exposed, and taking them altogether, are they not 

 the product of a condensation of very light atoms of an unknown 

 primordial matter, which is perhaps ether ? 



Thus is brought forward afresh, from considerations taken 

 from the constitution of the universe, this question of the 

 unity of matter which chemistry has before raised from a con- 

 sideration of the relative weight of atoms. It is not solved, and 

 it is probable that it never will be in the sense here indicated. 

 Everything leads to the belief in the diversity of matter, and the 

 indestructible, irreducible nature of atoms. Does it not require 

 as M. Berthelot has pointed out, the same quantity of heat to put 

 them in motion, whether they are heavy or light, and ought not 

 the law of Petit and Dulong to prevail in its simplicity against 

 the opposite hypothesis, however ingenious it may be ? 



I have endeavoured, gentlemen, to trace out for you the most 

 recent progress accomplished in chemistry, in physics, and in 

 physical astronomy, sciences so diverse in their object, but which 

 have a basis in common — matter — and one supreme object — a 

 knowledge of its constitution and of its properties and of its dis- 

 tribution in the universe. They teach us that the worlds which 

 people infinite space are made like our own system, and that 

 this great universe is all movement, co-ordinated movement. But 

 new and marvellous fact, this harmony of the celestial spheres of 

 which Pythagoras spoke, and which a modern poet has cele- 

 brated in immortal verse, is met with in the world of the in- 

 finitely little. There also all is co-ordinated movement, and 

 these atoms, whose accumulation forms matter, have never any 



